feat: add web UI, query engine, session management, and 20 E2E tests

- Web UI: login, dashboard, links CRUD, collections, API keys, admin pages
- Query engine: AND/OR/XOR with field filters, tag search, preview endpoint
- Session management: token expiry detection, 401 interceptor, expiry banner
- Links search: tags included, multi-word AND, query mode with set operations
- Collections: static/dynamic, query builder with preview, public tree view
- Save as Collection: convert search results (static) or query (dynamic)
- Dashboard stats: resilient loading with allSettled pattern
- Login page: redesigned with public collections tree view
- Bug fix: query executor None fields crash (notes/description/url/title)
- E2E tests: 20 Playwright tests covering all critical user flows
- All 104 tests passing (84 unit/integration + 20 E2E)

LinkSyncServer/queries/executor.py

@@ -51,10 +51,11 @@ def _evaluate_node(node: Dict[str, Any], bookmarks: List[Dict[str, Any]]) -> set
         return {
             b["id"]
             for b in bookmarks
-            if value in b.get("title", "").lower()
-            or value in b.get("description", "").lower()
-            or value in b.get("url", "").lower()
-            or value in b.get("notes", "").lower()
+            if value in (b.get("title") or "").lower()
+            or value in (b.get("description") or "").lower()
+            or value in (b.get("url") or "").lower()
+            or value in (b.get("notes") or "").lower()
+            or any(value in t.lower() for t in (b.get("tags") or []))
         }
 
     if operation == "TERM_SET":
@@ -63,9 +64,10 @@ def _evaluate_node(node: Dict[str, Any], bookmarks: List[Dict[str, Any]]) -> set
         result = set()
         for b in bookmarks:
             text = (
-                f"{b.get('title', '')} {b.get('description', '')} {b.get('url', '')} {b.get('notes', '')}"
+                f"{(b.get('title') or '')} {(b.get('description') or '')} {(b.get('url') or '')} {(b.get('notes') or '')}"
             ).lower()
-            if any(term in text for term in terms_lower):
+            tags_lower = [t.lower() for t in (b.get("tags") or [])]
+            if any(term in text for term in terms_lower) or any(term in tags_lower for term in terms_lower):
                 result.add(b["id"])
         return result